A muscle can be described as:

A muscle is indeed best described as tissue that contracts to provide movement. Muscles are essential components of the musculoskeletal system and play a crucial role in facilitating movement by contracting and relaxing. When a muscle contracts, it generates force that can pull on bones, enabling motion of the body parts these muscles are attached to. This function is fundamental for activities ranging from voluntary movements, such as walking or lifting objects, to involuntary movements, like the beating of the heart.

The other descriptions presented do not accurately define a muscle. The first option refers more to joints, where bones articulate and come together. The second option describes ligaments, which are tissues that connect bones to other bones and provide stability to joints. The fourth option pertains to tendons, which connect muscles to bones, enabling the muscles' force to be transferred for movement. Thus, identifying a muscle specifically as tissue that contracts to enable movement is both accurate and aligns with the basic understanding of muscular function in physical education.